gatefold vs foldout

gatefold and foldout both are nouns.

Word	Noun	Adjective	Verb	Adverb
gatefold	Yes	No	No	No
foldout	Yes	No	No	No

As nouns, gatefold and foldout are synonyms defined as:

gatefold and foldout: an oversize page that is folded in to a book or magazine

gatefold (noun)	foldout (noun)
an oversize page that is folded in to a book or magazine	an oversize page that is folded in to a book or magazine